1. Field of the Invention
The present invention relates to a charging contact plate, and more particularly, to a charging contact plate for preventing the shifting in the longitudinal direction of a primary charge roller of a cartridge used in a printer and for charging the primary charge roller.
2. Description of the Prior Art
Please refer to FIG. 1, which is a schematic diagram of a conventional charging device for charging a primary charge roller 8 of a cartridge used in a printer. The conventional charging device includes a charging contact point 8a, a metallic plate 8b, a coil spring 8c and a bearing 8d. The charge bias is applied from the charging contact point 8a to the primary charge roller 8.
The charging contact point 8a is a portion of the metallic plate 8b and connected with a power supply of the printer. The metallic plate 8b is contacted with one end the coil spring 8c. The bearing 8d is disposed at the other end of the coil spring 8c. And the bearing 8d serves to support the primary charge roller 8. Therefore, contact point 8a, a metallic plate 8b, a coil spring 8c and a bearing 8d form a conductive line for charging the primary charge roller 8.
However, since the conventional charging device is assembled by a number of portions, it is not a direct conductive line for connecting the primary charge roller 8 and the power supply of the printer, and it would result in the problems of electric conduction. The conventional charging device won""t form a conductive line and can""t charge the primary charge roller 8, when one portion of the conventional charging device doesn""t contact the other portions properly.
Moreover, due to the conventional charging device being assembled by a number of portions, it would have large volume and be heavy, and there should be large room within the cartridge for containing it. Thus, the printer must be large and heavy, too. Therefore, this kind of design is inefficient and causes high cost.
Additionally, since the primary charge roller 8 may shift back and forth in the longitudinal direction as it rotates, it would hamper the image output quality of the printer. Further, this instability will cause the wear of the bearing 8d and the primary charge roller 8 and make the primary charge roller 8 more instable. Therefore, this kind of design has low image output quality.
It is an objective of the present invention to provide a charging contact plate for forming a direct conductive line for connecting the primary charge roller and the power supply of the printer. The charging contact plate is made integrally of a piece of elastically conductive material. It has two opposed ends for connecting the power supply of the printer and the primary charge roller, respectively. Therefore, it wouldn""t have the problems of electric conduction.
Another objective of the present invention is to provide a charging contact plate for reducing the volume and weight of the printer. Since the charging contact plate is made integrally by a piece of elastically conductive material, it can be made to be a small and light one. Therefore, the printer can be made to be small and light, too.
The further objective of the present invention is to provide a charging contact plate for preventing the primary charge roller form shifting back and forth in the axial direction as it rotates. When one end of the charging contact plate is secured on the cartridge of the printer, the other end of the charging contact plate will press one end of the primary charge roller and force the primary charge roller to be stable by the elasticity of the charging contact plate.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment illustrated in the various figures and drawings.